Lincoln 1921 a digital multimeter, The element resistance should be as follows, 208V - 43 ohms

		a digital multimeter.
		The element resistance should be as follows:
		208V – 43 ohms	approx.
		240V – 57 ohms	approx.
		Replace heating elements as needed.
No Infrared Heating	Main fan motor	Check for main fan operation. If it is not operating, refer
		to “Oven fan will not run”.
	Air pressure switch	Check for 208/240VAC to the air pressure switch. If no
		voltage is present, trace wiring back to main power
		switch. This normally open switch should close when
		the main fan is activated. Refer to the “Removal and
		installation” section for proper adjustment. Replace as
		needed.
	Switch, Infrared heater	Check for 208/240VAC to the Infrared heater switch. If
		no voltage is present, trace wiring back to the air
		pressure switch. WITH POWER OFF: Check continuity
		between switch terminals. Replace switch as needed.
	Infrared heater relay	Check for supply voltage to the relay coil. If no voltage
		is present, trace wiring back to Infrared heater switch. If
		voltage is present and the relay will not activate,
		replace the Infrared heater relay. Also check each relay
		contact for high voltage input and output.
	Infrared Heating element(s)	Check the Amp draw on each power leg for proper
		load. Check the specification plate for rating
		information. If the amp draw is high or low, check the
		individual elements for opens, shorts and proper
		resistance.
		WITH POWER OFF: To check resistance of the
		elements, remove all leads from the elements and use
		a digital multimeter.
		The element resistance should be as follows:
		208V – 45 ohms	approx.
		240V – 58 ohms	approx.
		Replace heating elements as needed.
Oven heats with switch off	Main heater relay or	The Main heater relay or Infrared heater relay has
	Infrared heater relay	probably failed in the closed position. If there is no
		voltage to the operating coil, but there is high voltage at
		the relay output, replace the heater relay.
Intermittent heating	Thermal/overload of motor	The main fan motor is equipped with internal thermal
		protection and will cease to operate if overheating
		occurs. As the motor overheats and then cools, this will
		cause the oven to cycle on and off intermittently.
		Improper ventilation or lack of preventive maintenance
		may cause this. Also, most of the problems listed under
		“Oven will not heat” can cause intermittent failure.
Conveyor will not run	NOTE: Display will indicate
	“Belt Jam”
	Power supply	Check circuit breakers, reset if required. Check power
		plug to be sure it is firmly in receptacle. Measure
		incoming power, call power co. if needed.
	Fuse, 10 Amp	Check, replace if necessary.
	Fuse holder	Check, replace if necessary.
	Hi-limit thermostat, oven cavity	Terminals are normally closed. If open, reset
		thermostat and retest. If thermostat will not hold for
		maximum oven temperature, and oven is not exceeding
		temperature setting, check for proper location of
		capillary bulb in its spring holder. If the capillary checks
		okay, replace the hi-limit thermostat.
8			DTF – 1920 Series Service Manual